Just installed 1.20 on HP DV7 laptop with Win7 64bit. When defrag completed, there was still over 7Gb of fragmented files. I really like the interface of Defraggler, I haven't seen a version yet that does a thorough defrag.
Add C:\System Volume Information\ (a.k.a. the folder where System Restore Points and Shadow Copies are) to Defraggler's exclude list. You'll need to enable system files/folders view in Windows Explorer's Folder Options firs